The soundscape of the Anthropocene ocean Duarte, Carlos M; Chapuis, Lucille; Collin, Shaun P ...
Science (American Association for the Advancement of Science),
02/2021, Letnik:
371, Številka:
6529
Journal Article
Recenzirano
Odprti dostop
Oceans have become substantially noisier since the Industrial Revolution. Shipping, resource exploration, and infrastructure development have increased the anthrophony (sounds generated by human ...activities), whereas the biophony (sounds of biological origin) has been reduced by hunting, fishing, and habitat degradation. Climate change is affecting geophony (abiotic, natural sounds). Existing evidence shows that anthrophony affects marine animals at multiple levels, including their behavior, physiology, and, in extreme cases, survival. This should prompt management actions to deploy existing solutions to reduce noise levels in the ocean, thereby allowing marine animals to reestablish their use of ocean sound as a central ecological trait in a healthy ocean.
Anthropogenic noise across the world's oceans threatens the ability of vocalizing marine species to communicate. Some species vocalize at key life stages or whilst foraging, and disruption to the ...acoustic habitat at these times could lead to adverse consequences at the population level. To investigate the risk of these impacts, we investigated the effect of vessel noise on the communication space of the Bryde's whale Balaenoptera edeni, an endangered species which vocalizes at low frequencies, and bigeye Pempheris adspersa, a nocturnal fish species which uses contact calls to maintain group cohesion while foraging. By combining long‐term acoustic monitoring data with AIS vessel‐tracking data and acoustic propagation modelling, the impact of vessel noise on their communication space was determined. Routine vessel passages cut down communication space by up to 61.5% for bigeyes and 87.4% for Bryde's whales. This influence of vessel noise on communication space exceeded natural variability for between 3.9 and 18.9% of the monitoring period. Additionally, during the closest point of approach of a large commercial vessel, <10 km from the listening station, the communication space of both species was reduced by a maximum of 99% compared to the ambient soundscape. These results suggest that vessel noise reduces communication space beyond the evolutionary context of these species and may have chronic effects on these populations. To combat this risk, we propose the application or extension of ship speed restrictions in ecologically significant areas, since our results indicate a reduction in sound source levels for vessels transiting at lower speeds.
Anthropogenic noise across the world's oceans threatens the ability of vocalizing marine species to communicate. Vessel noise reduced communication space beyond natural variation and routinely reduced communication space by up to 61.5% for bigeyes and 87.4% for Bryde's whales. These results suggest vessel noise could affect critical life history strategies that require the use of sound for communication.
Summary
Diversity measurement techniques can present logistical and financial obstacles to conservation efforts. Ecoacoustics has recently emerged as a promising solution to these issues, providing a ...mechanism for measuring diversity using acoustic indices, which have proven to be beneficial in terrestrial habitats. This study investigates the application of acoustic measures as a tool for quick and effective marine diversity monitoring via direct, in situ comparison of ecoacoustics indices with species assemblage diversity measures from temperate rocky reefs.
Acoustic recordings and visual surveys of reef fish abundance were collected at nine sites in north‐eastern New Zealand. Three ecoacoustic indices originally developed for terrestrial use were then compared to three species assemblage diversity measures and compared using Pearson correlations. Additionally, four criteria for successful ecoacoustic indices were developed and tested as a means of standardizing future evaluation and use of acoustic indices: (i) positive correlations between species diversity and ecoacoustic indices in relevant frequency ranges, (ii) robustness to changes in spectral resolution, (iii) robustness to the presence of natural noise interference (i.e. wind) and (iv) robustness to the presence of anthropogenic noise.
Acoustic Complexity Index (ACI) was significantly correlated with Pielou's Evenness (J′) and Shannon's index (H′). Neither Acoustic Richness (AR) nor ACI was impacted by changes in spectral resolution, but values of the Acoustic Entropy Index (H) increased significantly between fast Fourier transformation (FFT) sizes 512 and 1024. H was consistently positively correlated with both H′ and estimated number of species (S) above a spectral resolution of c. 140·6 Hz (FFT size 1024). Wind did not affect any of the acoustic indices. As anthropogenic noise was included in these investigations, both ACI and H were considered robust to its presence.
While AR failed to meet all four criteria for a successful ecoacoustic indices, both ACI and H appeared to be appropriate for use on temperate reefs. In a time of accelerated global diversity loss, these two ecoacoustic indices show strong potential for use as efficient, non‐invasive marine diversity measures.
The sensory systems of crustaceans (aquatic decapods and stomatopods) have adapted to a diverse range of aquatic ecosystems. Sound production in aquatic crustaceans is more widespread than previously ...thought, and has been shown to play a major role in many of their life-history strategies; however, there are still many gaps in our understanding of their sound reception abilities. Crustaceans have three main sensory receptors for sound - the statocyst, superficial hair cells and chordotonal organs - which are all sensitive to the particle motion component of the sound field, rather than the pressure component. Our current understanding of these receptors is that they are sensitive to low-frequency sounds (<2000 Hz). There are a wide variety of sound-producing mechanisms employed by these animals, ranging from stridulation to implosive cavitation (see Glossary). These signals are used for a range of social behaviours, such as courtship, territorial defence and assessing 'resource guarding'. Furthermore, there are examples of sound signals that exceed their hearing range, highlighting a mismatch in our understanding of their hearing systems. This mismatch provides weight to the suggestion that another sound transmission channel - substrate-borne vibrations - might be at play, particularly because most crustaceans live on or near the seafloor. Finally, suggestions are made regarding potential future work that is needed to fill the substantial gaps in our understanding of how crustaceans hear and produce sound.
From midnight of 26 March 2020, New Zealand became one of the first countries to enter a strict lockdown to combat the spread of COVID‐19. The lockdown banned all non‐essential services and travel ...both on land and sea. Overnight, the country's busiest coastal waterway, the Hauraki Gulf Marine Park, became devoid of almost all recreational and non‐essential commercial vessels. An almost instant change in the marine soundscape ensued, with ambient sound levels in busy channels dropping nearly threefold the first 12 h. This sudden drop led fish and dolphins to experience an immediate increase in their communication ranges by up to an estimated 65%. Very low vessel activity during the lockdown (indicated by the presence of vessel noise over the day) revealed new insights into cumulative noise effects from vessels on auditory masking. For example, at sites nearer Auckland City, communication ranges increased approximately 18 m (22%) or 50 m (11%) for every 10% decrease in vessel activity for fish and dolphins, respectively. However, further from the city and in deeper water, these communication ranges were increased by approximately 13 m (31%) or 510 m (20%). These new data demonstrate how noise from small vessels can impact underwater soundscapes and how marine animals will have to adapt to ever‐growing noise pollution.
Dolphins and fish within New Zealand's Hauraki Gulf experience daily median estimated communication ranges up 2.9 km and 4 m. These ranges are limited because vessel noise is present up to approximately 70% of a 24‐h period. However, when New Zealand entered a 7‐week community lockdown to combat the spread of COVID‐19, all small non‐essential vessels were banned from operating. Daily vessel noise presence decreased dramatically, reaching as low as 8%. This meant that the estimated communication ranges in dolphins and fish swelled to over 4 km and 150 m, respectively.
Anthropogenic stressors, such as plastics and fishing, are putting coastal habitats under immense pressure. However, sound pollution from small boats has received little attention given the ...importance of sound in the various life history strategies of many marine animals. By combining passive acoustic monitoring, propagation modelling, and hearing threshold data, the impact of small-boat sound on the listening spaces of four coastal species was determined. Listening space reductions (LSR) were greater for fishes compared to crustaceans, for which LSR varied by day and night, due to their greater hearing abilities. Listening space also varied by sound modality for the two fish species, highlighting the importance of considering both sound pressure and particle motion. The theoretical results demonstrate that boat sound hinders the ability of fishes to perceive acoustic cues, advocating for future field-based research on acoustic cues, and highlighting the need for effective mitigation and management of small-boat sound within coastal areas worldwide.
Considerable diversity has been documented in most sensory systems of elasmobranchs (sharks, rays, and skates); however, relatively little is known about morphological variation in the auditory ...system of these fishes. Using magnetic resonance imaging (MRI), the inner ear structures of 26 elasmobranchs were assessed in situ. The inner ear end organs (saccule, lagena, utricle, and macula neglecta), semi-circular canals (horizontal, anterior, and posterior), and endolymphatic duct were compared using phylogenetically-informed, multivariate analyses. Inner ear variation can be characterised by three primary axes that are influenced by diet and habitat, where piscivorous elasmobranchs have larger inner ears compared to non-piscivorous species, and reef-associated species have larger inner ears than oceanic species. Importantly, this variation may reflect differences in auditory specialisation that could be tied to the functional requirements and environmental soundscapes of different species.
Sound perception and detection in decapod crustaceans is surprisingly poorly understood, even though there is mounting evidence for sound playing a critical role in many life history strategies. The ...suspected primary organ of sound perception is the paired statocysts at the base of the first antennal segment. To better understand the comparative sound detection of decapods, auditory evoked potentials were recorded from the statocyst nerve region of four species (Leptograpsus variegate, Plagusia chabrus, Ovalipes catharus, Austrohelice crassa) in response to two different auditory stimuli presentation methods, shaker table (particle acceleration) and underwater speaker (particle acceleration and pressure). The results showed that there was significant variation in the sound detection abilities between all four species. However, exposure to the speaker stimuli increased all four species sound detection abilities, in terms of both frequency bandwidth and sensitivity, compared with shaker table-derived sound detection abilities. This indicates that there is another sensory mechanism in play as well as the statocyst system. Overall, the present research provides comparative evidence of sound detection in decapods and indicates underwater sound detection in this animal group was even more complex than previously thought.
While sound is a useful cue for guiding the onshore orientation of larvae because it travels long distances underwater, it also has the potential to convey valuable information about the quality and ...type of the habitat at the source. Here, we provide, to our knowledge, the first evidence that settlement-stage coastal crab species can interpret and show a strong settlement and metamorphosis response to habitat-related differences in natural underwater sound. Laboratory- and field-based experiments demonstrated that time to metamorphosis in the settlement-stage larvae of common coastal crab species varied in response to different underwater sound signatures produced by different habitat types. The megalopae of five species of both temperate and tropical crabs showed a significant decrease in time to metamorphosis, when exposed to sound from their optimal settlement habitat type compared with other habitat types. These results indicate that sounds emanating from specific underwater habitats may play a major role in determining spatial patterns of recruitment in coastal crab species.
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